Why are there only two green branches?
I cant tell you why (I'm no scientist) but something like that happens sometimes.
by Whoandwhatitis moderator
@DigiDong, All those tiny dots you see in the grey area are all "points" where particles interacted with the various detectors.
This FAQ discussion has many parts that are relevant to your question: http://talk.higgshunters.org/#/boards/BHH0000001/discussions/DHH00000np
In particular, this one:
Q: What if I can't find any OCVs in a picture? - A: That's OK. Not all
pictures have OCVs. Just move on to the next picture.
From @andy.haas in this discussion: http://talk.higgshunters.org/#/boards/BHH0000004/discussions/DHH000002t
The lines (curved lines) are paths reconstructed by the computer by
joining the hits together (the little dots you see all over the
tracker). The white lines could not be matched by the computer with a
vertex. This is the hard part.
First, it's true that the lowest energy tracks are deliberately left
out of the images, to make it easier to identify the higher-energy,
more interesting tracks we expect from off-center vertices. The
low-energy tracks curl up more in the magnetic field. You might see
some evidence for them in the grey hit-maps in the background, but we
don't flag them with lines.
Hope this helps!